From 1973 to July 1990, 183 kidney transplantations were performed at the Transplantation Unit of the Department of Urology--Faculty of Medicine--University of Zagreb. Out of these, 57 were from the living related donors. The research included 50 (88%) living related donors (28 mothers, 12 fathers, 5 brothers and 5 sisters) followed up from 1 to 15 years after donor nephrectomy. The donors' health conditions were evaluated by clinical-laboratory examinations (biochemical tests, renal function tests, urinoculture, ultrasound, isotopic renal studies, arterial blood pressure). In 48 (96%) neither morphological nor functional changes of the urinary system were found. A certain number of donors requested a transfer to less physically strenuous jobs. Except for the grafts functioning well in the recipients, the results also showed that the quality of donors' lives remained unchanged.